Device for electrically contacting a sectionally insulated external conductor of a coaxial cable

ABSTRACT

A device for electrically conductively contacting a sectionally stripped outer conductor of a coaxial cable is provided. The device includes a main body that can be clamped about the cable that is to be contacted. In a non-installed position, the main body is open in a circumferential direction to form ends, which are provided with angled-off or bent-away tongues made at least in part metal. In an installed position, sealing surfaces of elastic material are formed on surfaces of the tongues that face one another. In the installed position, the tongues can be interconnected by at least one screw or bolt. The device also includes a mechanism for limiting a screw-in extent of the screws such that a compression of the elastic material of the sealing surfaces is effected in a defined manner when the screws are tightened.

[0001] The invention relates to a device of the type mentioned in theintroductory portion of claim 1 for the electrical conductive contactingof a stripped outer conductor of a coaxial cable.

[0002] EP 0 744 788 A1 discloses a device of the pertaining type thathas a main body that is embodied as a clamp that can be clamped aboutthe cable that is to be contacted, with the main body being open in thecircumferential direction and being provided at its ends with angled-offtongues, with sealing surfaces of elastic material being formed on thosesurfaces of the tongues that in the installed position face one another,whereby in the installed position of the device, the tongues areinterconnected by screws. With the known device, the main body has aband-shaped metallic clamp that is embedded in elastic material, wherebyon that side that in the installed position faces the object that is tobe contacted, a contact surface is left exposed for a contact elementfor contacting the stripped region of the coaxial cable.

[0003] A drawback of the known device is that if during installation ofthe device on the coaxial cable the screws for connecting the main bodyare tightened with excessive force, the elastic material of the sealingsurfaces on the tongues is compressed excessively and in a non-definedmanner, resulting in the danger that the elastic material becomesdamaged and the sealing surfaces thereby lose their sealing effect.

[0004] It is an object of the invention to provide a device of the typementioned in the introductory portion of claim 1 that does not have thedrawback of the known device and that thus reduces the danger that whenthe screw are tightened, the elastic material of the sealing surfaceswill be excessively compressed.

[0005] This object is realized by the teaching provided in claim 1.

[0006] The basic concept of the inventive teaching is that means forlimiting the screw-in extent of the screws is provided such that acompression of the elastic material of the sealing surfaces is effectedin a defined manner when the screws are tightened. This reliablyprevents the elastic material of the sealing surfaces from beingexcessively compressed during tightening of the screws and therebypossibly becoming damaged. Rather, the compression of the elasticmaterial is effected in a defined manner, whereby the amount of thecompression can in a simple manner be as desired by appropriatedimensioning of the means for limiting the screw-in extent and hence themaximum possible screw-in extent.

[0007] As a consequence of the inventively provided means for limitingthe screw-in extent, the installation of the inventive device issimplified and can hence also be readily carried out by inexperiencedpersonnel.

[0008] The inventive device is straightforward and can hence be producedin an economical manner and have a sturdy construction.

[0009] The means for limiting the screw-in extent can, in conformitywith the respective requirements, be embodied in any suitable manner,for example by having the thread of the screw end at an axial spacingfrom its head, so that the screw-in extent is limited by the length ofthe thread.

[0010] An extremely advantageous further development of the basicconcept of the inventive teaching provides that the means for limitingthe screw-in extent be formed by a stop means. This embodiment makes itpossible in a particularly simple manner to limit the screw-in extent.

[0011] In conformity with the respective requirements, the stop can bedisposed on the screw, especially can be formed on the screw, or thestop can be disposed on one of the tongues, in particular can be formedon one of the tongues. With the embodiment where the stop is formed onthe screw or on one of the tongues, there is no need for an additionalcomponent to form the stop, so that the construction of the inventivedevice is further simplified and made more economical.

[0012] A further development of the embodiment where the stop is formedon one of the tongues provides that the stop be formed by at least oneprojection, which of one of the tongues extends in the axial directionof the screw, and is disposed on that side that in the installedposition faces the head of the screw; the projection is formed such thatat the end of the screw-in extent, the head comes to rest against theprojection. With this embodiment, the projection can be formed, forexample, by at least one nose or the like that is formed on the tongue.

[0013] Pursuant to a further development of the inventive teaching, thestop is formed by a disc or sleeve that surrounds the shaft of thescrew, and that in the installed position is disposed between the headof the screw and the facing tongue. This embodiment has the advantagethat not only for the screw but also for the disc that forms the stop,standard components can be utilized, so that also with this embodimentthe inventive device is particularly easy and hence economical tomanufacture.

[0014] In the installed position of the device, the screw expedientlyextends through a through bore that is formed in one of the tongues, andis screwed into a threaded bore that is formed in the other tongue.

[0015] If, for example, the main body of the inventive device is made ofthin sheet metal, then to increase the stability, and to achieve anadequate depth, especially of the threaded bore, it is expedient for thetongues to be provided with reinforcing elements, preferably of metal,in which the bores are formed.

[0016] Pursuant to a further embodiment where the stop is formed on thescrew, the screw is provided between its head and its threaded end witha thread-free region, the diameter of which is greater than the diameterof the thread such that a shoulder is formed, whereby the diameter ofthe through bore in the tongue corresponds to or is greater than thediameter of the screw in the region of the shoulder such that the axialend face of the shoulder in the screw-in position rests against thatsurface of the other tongue that faces this tongue.

[0017] The invention will be explained in greater detail subsequentlywith the aid of the accompanying drawings, in which embodiments areillustrated.

[0018] Shown are:

[0019]FIG. 1 in a schematic perspective view, a first embodiment of theinventive device in the form of a clamp,

[0020]FIG. 2 a view of the radial inner surface of the device of FIG. 1without the contact element,

[0021]FIG. 3 in the same illustration as in FIG. 2, the device of FIG. 2with a contact element secured to the main body,

[0022]FIG. 4 a cross-sectional view taken along a line IV-IV through thedevice of FIG. 3 in the installed position,

[0023]FIG. 5 in a schematic perspective view, the device of FIG. 1 inthe installed position,

[0024]FIG. 6 a very schematic radial cross-sectional view through thedevice of FIG. 1 in the installed position to clarify the basicprinciple of the inventive teaching,

[0025]FIG. 7 a very schematic plan view and cross-sectional view of areinforcing element provided with a stop, and

[0026]FIG. 8 in the same illustration as in FIG. 7, a modification ofthe reinforcing element of FIG. 7.

[0027] In the figures of the drawings, the same or correspondingcomponents are provided with the same reference numerals.

[0028] A first embodiment of an inventive device 2 is illustrated inFIG. 1 and has a flexible main body 4 that is embodied as a clamp andthat in this embodiment is embodied as one piece and is open in thecircumferential direction, and at its free ends has angled-off tongues6,8 that in the installed position, in a manner that will be explainedin greater detail subsequently, can be interconnected by screws or boltsthat are not illustrated in FIG. 1.

[0029] The main body 4 has a band-shaped metal portion 10, as well as aportion 12 of elastic material, in the embodiment an elastomer, in whichthe axial edges of the metal portion 10 are embedded and are thusconnected with the portion 12 of elastic material (FIG. 4). The metalportion 10 extends in the peripheral direction right into the tongues6,8 and, in this region, for stabilization, is reinforced withplate-shaped reinforcing elements 5,7 of metal that can, for example, befused or welded with the metal portion 10. Formed in the tongue 9 arethreaded bores 9, 11, and formed in the tongue 8 are through bores 13,15, which, in a manner that will be explained in greater detailsubsequently, serve to receive screws or bolts that are not illustratedin FIG. 1, and by means of which the tongues 6,8 can be interconnectedin the installed position.

[0030] From FIG. 1 it cannot be seen, and therefore it will be hereexplained, that the surfaces of the tongues 6,8 that in the installedposition face one another are provided with an elastic material, forexample an elastomer, so that sealing surfaces are formed that in theinstalled position of the device 2 rest against one another in a sealingmanner.

[0031] On that side that in an installed position faces a coaxial cablethat is to be contacted, the portion 12 of elastic material formssealing lips 14,16 and, in this embodiment, respective further sealinglips 18, 20 that in the axial direction are disposed outwardly of thesealing lips 14,16. In the installed position, the sealing lips 14,16 aswell as the further sealing lips 18,20 of the main body 4 rest sealinglyagainst an outer surface of the object that is to be contacted, so thata space that in the installed position is formed between the object thatis to be contacted and the main body 4 is sealed off against penetrationof air and/or moisture.

[0032] The device 2 furthermore has a contact element, which is notillustrated in FIG. 1, to establish an electrically conductiveconnection with the coaxial cable that is to be contacted; in theinstalled position, the contact element is held on that side of the mainbody that faces the coaxial cable that is to be contacted, in otherwords, in the embodiment of FIG. 1 on a radially inner surface 22 of themain body 4, which forms a support surface, with the contact elementbeing held, for example, via an adhesive.

[0033] For the adjustment of the contact element during the manufactureof the device 2, the device 2 furthermore has adjustment aids for thecontact element, which with this embodiment are formed by contact orabutment edges 28, 30, 32 that are formed on ribs 34, 36, 38 that inturn are formed on the sealing lips 14,16 of the portion 12 of elasticmaterial.

[0034] The ribs 34,36 extend inwardly in an axial direction from theaxial edge 26 of the main body 4, while the rib 38 extends in an axialdirection inwardly from the opposite axial edge 26, whereby the ribs 34,36 are disposed on a circumferential line 33, and the rib 38 is disposedon a circumferential line 35 that is axially offset relative to thecircumferential line 33.

[0035]FIG. 2 is a view onto the radially inner surface 22 of the device2.

[0036]FIG. 3 shows the device 2 with a contact element 40 that is heldthereon and that with this embodiment is comprised of electricallyconductive graphite and in the plan view has an essentially rectangularconfiguration. The contact element 40 is connected by adhesive to theradially inner surface 22 of the main body 4 and is thus held thereon.

[0037] From FIG. 3 it can be seen that in the mounting positionillustrated therein, oppositely disposed portions of the edge of thecontact element 40 rest against the abutment edges 28, 30, 32 of theribs 34, 36, 38, which form centering means for centering the contactelement 40 between the oppositely disposed axial edges 24, 26 of themain body 4. The abutment edges 28, 30, 32 ensure that the contactelement 40 is held on the main body 4, and does not project laterallybeyond it in the desired position in which the long sides of the contactelement extend essentially parallel to the axial edges 24, 26 of themain body 4.

[0038]FIG. 4 shows a cross-sectional view taken along the line IV-IV inFIG. 3, whereby the device 2 is illustrated in the installed position inwhich the main body 4 rests against a coaxial cable 42 that is to becontacted via the sealing lips 14, 16 and the further sealing lips 18,20. To contact a sectionally stripped outer conductor 34 of the coaxialcable 42 in a contact region 46, the contact element 40 projects in aradial direction toward the coaxial cable 42 to such an extent that withthe sealing lips 14, 16 and 18, 20 resting against a sheathing 48 of thecoaxial cable 42, the contact element rests against the stripped outerconductor 44, which is recessed in a radial direction, and thusestablishes an electrically conductive connection with the outerconductor.

[0039]FIG. 5 shows the device 2 of FIG. 1 in the installed position inwhich the main body 4 extends about a coaxial cable 42 that is to becontacted in a sleeve-like manner. To secure the device 2 to the coaxialcable 42, an axial portion of the coaxial cable is first stripped, andsubsequently the main body 4, which is embodied as a clamp, is clampedabout the coaxial cable 42 that is to be contacted by means of metalscrews or bolts 50, 52 that extend through the through bores 13, 15formed in the tongue 8 and engage in the threaded bores 9, 11 formed inthe tongue 6.

[0040] During the clamping of the main body 4, the sealing lips 14, 16and the further sealing lips 18, 20 come to rest sealingly against thesheathing 48 of the coaxial cable 42, so that the sealing lips seal offthe space that in the installed position is formed between the coaxialcable 42 and the main body 4 against the penetration of air and/ormoisture. In the circumferential direction of the main body 4, thisspace is sealed as a result of the sealing surfaces, which are formed onthe tongue 6,8, coming to rest sealingly against one another, wherebythe elastic material of the sealing surfaces is pressed together orcompressed.

[0041] During the clamping of the main body 4, the contact element 40furthermore comes to rest against the stripped outer conductor 44 of thecoaxial cable 42, so that by means of the contact element 40 anelectrically conductive connection is established between the outerconductor 44 and the metal portion 10 of the main body 4. Since themetal portion 10 extends right into the tongues 6,8, it is possible viathe screws 50, 52 to establish an electrically conductive connection toa conductor, for example a grounding cable 54 which is schematicallyindicated in FIG. 5. For this purpose, the grounding cable 54 can beconnected with the screw 50 by a connecting eye. There is thusestablished in the desired manner an electrically conductive connectionbetween the grounding cable 54 and the outer conductor 44 of the coaxialcable 42, so that this outer conductor 44 is grounded.

[0042] In order during tightening of the screws 50, 52 to avoid anexcessive compression of the elastic material of the sealing surfaces,means are provided pursuant to the invention for limiting the screw-inextent of the screws 50, 52, as will be explained in greater detailsubsequently with the aid of FIG. 6.

[0043]FIG. 6 shows in a very schematic manner a radial cross-sectionthrough the device 2 in the installed position in the region of thescrew 52, whereby for purposes of simplification, merely the metalportion 10, the reinforcing elements 5, 7 and the screw 52 areillustrated, with the remaining parts of the device 2 being left off.For reasons of illustration, the thickness of the reinforcing elements5, 7 is exaggerated.

[0044] As can be seen from FIG. 6, the screw or bolt 52, in the axialdirection between its head 56 and its threaded end 58, has a thread-freeregion 60, the diameter of which is greater than the diameter of thethread such that in the screw-in direction, at the front of the region60, a shoulder 61 is formed. The screw or bolt 50, which cannot be seenin FIG. 6, has a comparable configuration.

[0045] The diameter of the through bore 13 in the tongue 8 is, forreceiving the screw 52, somewhat greater than the diameter of thethread-free region 60 of the screw 52, while its threaded end 58 can bescrewed into the threaded bore 9.

[0046] When the screw 52 is screwed into the threaded bore 9, thetongues 6, 8 are secured with one another, whereby the elastic materialof the sealing surfaces, which is designated with the reference numerals62, 64 in FIG. 6, is compressed or pressed together. When a maximumscrew-in extent, which is determined by the axial spacing of the axialend face of the shoulder 61 from the free end of the screw 52, isachieved, the end face of the shoulder 61 comes to rest in a definedmanner against that side of the reinforcing element 7 of the tongue 8that faces the tongue 6 in the manner of a stop, so that a furtherscrewing-in of the screw 52, and hence a further compression of theelastic material 62, 64 of the sealing surfaces, is prevented.

[0047] As a consequence of the stop, the screw-in extent is limited, sothat the amount of the compression of the elastic material is alsolimited. An excessive compression is thus reliably prevented.

[0048] The amount of the compression can be as desired based on theaxial spacing of the axial end face of the shoulder 61 from the free end66 of the screw 52.

[0049]FIG. 7 illustrates a further embodiment of a stop means forlimiting the screw-in extent. In this embodiment, the stop is formed byprojections or noses 68, 70 that are stamped out of the reinforcingelement 5 and are thus formed on the tongue 8. The noses 68, 70 extendaxially beyond the reinforcing element in the direction toward the headof a non-illustrated screw.

[0050] In contrast to Fig., the connection of the tongues 6, 8 iseffected with only a single screw, so that the tongue is provided withmerely one through bore 13. When being screwed into the threaded bore13, the non-illustrated screw, upon achieving a screw-in extent that ispredetermined by the axial length of the nose 68, 70, comes to restagainst the noses 68, 70 via the front end face, as viewed in thescrew-in direction, so that in this manner the screw-in extent and hencethe amount of compression of elastic material of the sealing surfaces islimited.

[0051]FIG. 8 illustrates a modification of the embodiment of FIG. 7,whereby the stop is formed by a disc 72 that is coaxial to thenon-illustrated screw. The disc 72 can be fixedly connected with thereinforcing element 7 or can be placed loosely thereon.

1. Device for the electrically conductive contacting of a sectionallystripped outer conductor of a coaxial cable, with a main body that isembodied as a clamp that can be clamped about the cable that is to becontacted and that is open in the circumferential direction and at itsends is provided with angled-off or bent-away tongues that are made atleast partially of metal and that on those surfaces that in theinstalled position face one another have formed sealing surfaces ofelastic material, whereby the tongues in the installed position, can beinterconnected by at least one screw, characterized in that, means areprovided for limiting the screw-in extent of the screws (50, 52) suchthat a compression of the elastic material (62, 64) of the sealingsurfaces is effected in a defined manner when the screws (50, 52) aretightened.
 2. Device according to claim 1, characterized in that, themeans for limiting the screw-in extent of the screws (50, 52) have astop (61; 68, 70; 72).
 3. Device according to claim 2, characterized inthat, the stop (61) is disposed on the screw (50, 52).
 4. Deviceaccording to claim 3, characterized in that, the stop (61) is formed onthe screw (50, 52).
 5. Device according to claim 2, characterized inthat, the stop (68, 70; 72) is disposed on one of the tongues (6,8). 6.Device according to claim 5, characterized in that, the stop (68, 70) isformed on one of the tongues (6, 8).
 7. Device according to claim 6,characterized in that, the stop is formed by at least one projection(68, 70) that extends in the axial direction of the screw (52) and isdisposed on that side of one of the tongues that in the installedposition faces the head (56) of the screw (52), wherein the projectionis formed such that the head (56) of the screw comes to rest against theprojection (68) at the end of the screw-in extent.
 8. Device accordingto claim 2, characterized in that, the stop is formed by a disc (72) orsleeve that in the installed position surrounds the shaft of the screw(50, 52) and that in the installed position is disposed between the head(56) of the screw (50, 52) and the facing tongue (8).
 9. Deviceaccording to claim 1, characterized in that, in the installed positionthe screw (50, 52) extends through a through bore (13 or 15) that isformed in one of the tongues (8), and is screwed into a threaded bore (9or 11) that is formed in the other tongue (6).
 10. Device according toclaim 9, characterized in that, the tongues are provided withreinforcing elements (5, 7) preferably of metal in which the bores (9,11, 13, 15) are formed.
 11. Device assding to claim 10, characterized inthat, the screws (50, 52) between their head and their threaded end, areprovided with a thread-free region (60) the diameter of which is greaterthan the diameter of the thread such that a shoulder (61) is formed,whereby the diameter of the through bore (13, 15) in the one tongue (8)corresponds to or is greater than the diameter of the screw (50, 52) inthe region of the shoulder (61) such that the axial end face of theshoulder (61), in the screw-in position, rests against that surface ofthe other tongue (6) that faces this tongue (8).
 12. Device according toclaim 2, characterized in that, to connect the tongues (6,8) with oneanother, at least two screws (50, 52) are provided and in that a stop isassociated with each screw (50, 52).